CTSB and bipolar disorder: IPL, inferior parietal lobe; IFG, inferior frontal gyrus; ECN, executive connectivity network; PA, physical activity; MCCB, MATRICS Consensus Cognitive Battery; MDD, major depressive disorder; BD, bipolar disorder; PL, parietal lobe; CTSB, Human Cathepsin B; WM, white matter; PFC, prefrontal cortex; PC, parietal cortex; DSM IV, diagnostic and statistical manual of mental disorders fourth edition